JP2016186313A - Power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power transmission device capable of improving the set degree of freedom of the gear specifications while suppressing an increase in the manufacturing cost.SOLUTION: A power transmission device 1 includes a first sun wheel and a second sun wheel as inscribed wheels coaxially arranged on a center axis, a plurality of planetary wheels arranged on the inner periphery side of the first sun wheel, a first transmission member bridged over the outer peripheries of the plurality of first planetary wheels and engaging with the first sun wheel while being inscribed therewith, a plurality of second planetary wheels provided integrally with the plurality of first planetary wheels, a second transmission member bridged over the outer peripheries of the plurality of second planetary wheels and engaging with the second sun wheel while being inscribed therewith, and a carrier rotatably supporting the plurality of first planetary wheels and the plurality of second planetary wheels.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power transmission device that shifts and transmits rotational power using a planetary mechanism.

  As a power transmission device, Patent Document 1 discloses a transmission using a planetary mechanism. This transmission gears a stepped planetary gear integrally connected to a pair of coaxially arranged internal gears, and outputs reduced rotational power from one of the internal gears. Patent Document 2 discloses a transmission using a flexure meshing wave gear mechanism. In this wave gear device, a part of the flex spline is meshed with a set of circular splines set to different numbers of teeth, and the rotational difference between the set of circular splines is output as reduced rotational power. .

JP 2011-231842 A JP 2005-188740 A

  In addition to flexibility, the flex spline of the wave gear mechanism as described above is required to have a strength capable of withstanding a reverse load received from each internal tooth of a set of circular splines. Therefore, there is a concern about an increase in manufacturing cost due to the adoption of the wave gear mechanism. In addition, in order to prevent interference other than the meshing part of a set of circular spline and flex spline, the wave gear mechanism requires that each tooth module be set to be somewhat small. There are restrictions.

  This invention is made | formed in view of such a situation, and it aims at providing the power transmission device which can improve the setting freedom degree of a gear specification, suppressing the increase in manufacturing cost.

  (Claim 1) The power transmission device according to the present invention is arranged on the inner peripheral side of the first solar car and the first solar car and the first solar car which are inscribed vehicles coaxially arranged on the central axis. A plurality of first planetary wheels, a first transmission member that is wound around the outer periphery of the plurality of first planetary wheels and inscribed in engagement with the first solar wheel, and an inner peripheral side of the second solar wheel. A plurality of second planetary gears provided integrally with the plurality of first planetary vehicles, and a second transmission member that is wound around the outer periphery of the plurality of second planetary vehicles and is inscribed in engagement with the second solar wheel And a carrier that rotatably supports the plurality of first planetary vehicles and the plurality of second planetary vehicles.

  (Claim 6) The power transmission device according to the present invention is arranged on the inner peripheral side of the first solar car and the first solar car and the second solar car which are inscribed vehicles coaxially arranged on the central axis. A plurality of first planetary wheels, a first transmission member that is wound around the outer periphery of the plurality of first planetary wheels and inscribed in engagement with the first solar wheel, and inscribed in engagement with the second solar wheel. And a second planetary gear provided integrally with the plurality of first planetary vehicles, and a plurality of first planetary vehicles and a carrier that rotatably supports the second planetary vehicles.

  According to invention of Claim 1, the 1st transmission member and the 2nd transmission member which are separate members engage with a 1st solar wheel and a 2nd solar wheel. According to the invention described in claim 6, the first transmission member and the second planetary wheel, which are separate members, are engaged with the first solar wheel and the second solar wheel. Therefore, since the required strength of each member is reduced as compared with the strength required for the flex spline of the wave gear mechanism, it is possible to reduce the size of the apparatus while suppressing an increase in manufacturing cost.

  Further, by applying the above-described configuration, it is possible to apply a meshing type and friction type planetary mechanism to the power transmission device. In addition, since the first transmission member and the second transmission member (or the first transmission member and the second planetary gear) are separate members, in the case of the meshing planetary mechanism, the structure is similar to that of the wave gear mechanism. Since there are no restrictions, the degree of freedom in setting the gear specifications can be improved. In the case of a friction type planetary mechanism, the degree of freedom in setting the outer diameter and inner diameter of the friction wheel can be improved.

It is sectional drawing of the axial direction of the power transmission device in embodiment, and is II sectional drawing of FIG. It is II-II sectional drawing in FIG.

  Hereinafter, an embodiment in which a power transmission device of the present invention is embodied will be described with reference to the drawings. In the embodiment, the power transmission device exemplifies a configuration used in a reduction gear that decelerates and outputs a driving force input from a driving source using a planetary mechanism.

<Embodiment>
(Configuration of power transmission device 1)
The configuration of the power transmission device 1 according to the embodiment will be described with reference to FIGS. 1 and 2. In FIG. 2, as indicated by the cutting line in FIG. 1, cross sections at different positions in the direction of the central axis Ac are shown together. As shown in FIG. 1, the power transmission device 1 includes a housing 2, an input shaft 3, an output shaft 4, a cylindrical member 5, a first sun gear 11, a second sun gear 12, and two first gears. A single planetary gear 20, two second planetary gears 30, a first toothed belt 41, a second toothed belt 42, and a carrier 50 are configured.

  The housing 2 is a fixing member that constitutes a part of the outer peripheral shape of the reduction gear. The input shaft 3 and the output shaft 4 are shaft members that are rotatably supported by the housing 2 around the central axis line Ac. One end of the input shaft 3 is connected to rotate integrally with an output shaft of a drive source such as an electric motor. The other end of the input shaft 3 is connected to a carrier 50 described later. The output shaft 4 outputs the driving force decelerated by the power transmission device 1. The output shaft 4 is connected to a cylindrical member 5 disposed on the inner peripheral side of the housing 2 and rotates integrally with the cylindrical member 5.

  The first sun gear 11 (corresponding to the “first sun wheel” of the present invention) and the second sun gear 12 (corresponding to the “second sun wheel” of the present invention) are arranged coaxially on the central axis Ac. This is an inscribed vehicle. In the present embodiment, the first sun gear 11 and the second sun gear 12 are internal gears having internal teeth formed on the inner peripheral surface. The first sun gear 11 is fixed to the housing 2.

  The second sun gear 12 is arranged in parallel with the first sun gear 11 on the output side (right side in FIG. 1) of the power transmission device 1. The second sun gear 12 is connected to the output shaft 4 via the cylindrical member 5 and rotates integrally with the output shaft 4. In the present embodiment, the first sun gear 11 and the second sun gear 12 are set to different gear specifications. More specifically, the number of teeth of the first sun gear 11 is set to be larger than the number of teeth of the second sun gear 12.

  Each of the two first planetary gears 20 (corresponding to the “first planetary gear” of the present invention) is arranged at a circumferential position symmetrical about the central axis Ac on the inner peripheral side of the first sun gear 11. (Only one is shown on the upper side of FIG. 2). Each of the two second planetary gears 30 (corresponding to the “second planetary vehicle” of the present invention) is arranged at a circumferential position symmetrical about the central axis Ac on the inner peripheral side of the second sun gear 12. (Only one is shown at the bottom of FIG. 2).

  The first planetary gear 20 and the second planetary gear 30 are screwed together by bolts in a state where the respective bolt holes 22 and 32 are concentrically connected. Thus, the second planetary gear 30 is provided integrally with the first planetary gear 20 adjacent in the central axis Ac direction. The first planetary gear 20 and the second planetary gear 30 are external gears having external teeth formed on the outer periphery in the present embodiment. The first planetary gear 20 and the second planetary gear 30 are connected to a rotation axis Ap (two-dot chain line in FIG. 1) via a bearing by a planetary support shaft 51 of a carrier 50 that passes through shaft holes 21 and 31 formed in the center. ) It is supported rotatably around.

  In the first planetary gear 20, on the inner peripheral side of the first sun gear 11, the distance at which the outer periphery of the first planetary gear 20 is closest to the inner periphery of the first sun gear 11 is the thickness of the first toothed belt 41. It is supported by the carrier 50 so that Similarly, in the second planetary gear 30, the distance at which the outer periphery of the second planetary gear 30 is closest to the inner periphery of the second sun gear 12 on the inner peripheral side of the second sun gear 12 is the second toothed belt 42. It is supported by the carrier 50 so as to have a thickness.

  The first planetary gear 20 and the second planetary gear 30 have a pair of flanges 23 and 33 provided at both ends in the direction of the central axis Ac. The flanges 23 and 33 protrude radially outwardly over the entire circumference, and the first toothed belt 41 and the second toothed belt 42 are stretched around the outer circumferences of the first planetary gear 20 and the second planetary gear 30. Prevents falling off. The first planetary gear 20 and the second planetary gear 30 are set to different gear specifications. More specifically, the number of teeth of the first planetary gear 20 is set to be larger than the number of teeth of the second planetary gear 30.

  The first toothed belt 41 (corresponding to the “first transmission member” of the present invention) is an endless belt member (a half circumference is shown on the upper side in FIG. 2). The first toothed belt 41 is wound around the outer circumferences of the two first planetary gears 20. In the present embodiment, the first toothed belt 41 has external teeth 41 a that mesh with the first sun gear 11 and internal teeth 41 b that mesh with the two first planetary gears 20. The first toothed belt 41 is engaged with both gears and transmits rotational power at two locations around the central axis Ac while being sandwiched between the first sun gear 11 and the first planetary gear 20.

  The second toothed belt 42 (corresponding to the “second transmission member” of the present invention) is an endless belt member (a half circumference is shown on the lower side of FIG. 2). The second toothed belt 42 is wound around the outer circumferences of the two second planetary gears 30. In the present embodiment, the second toothed belt 42 has external teeth 42 a that mesh with the second sun gear 12 and internal teeth 42 b that mesh with the two second planetary gears 30. The second toothed belt 42 meshes with both gears and transmits rotational power at two locations around the central axis Ac while being sandwiched between the second sun gear 12 and the second planetary gear 30.

  The first toothed belt 41 and the second toothed belt 42 are formed of an elastic material such as rubber or resin having a relatively high hardness in this embodiment. Thereby, the first toothed belt 41 and the second toothed belt 42 are configured to be able to absorb the impact in the rotating path direction. Further, the number of external teeth 41 a of the first toothed belt 41 is set to a value equal to the number of internal teeth 41 b of the first toothed belt 41. Similarly, the number of outer teeth 42 a of the second toothed belt 42 is set equal to the number of inner teeth 42 b of the second toothed belt 42. In the present embodiment, the number of teeth of the first toothed belt 41 is set to be larger than the number of teeth of the second toothed belt 42.

  The carrier 50 is disposed coaxially with the input shaft 3 and is supported by the housing 2 so as to be rotatable about the central axis Ac. The carrier 50 rotatably supports the two first planetary gears 20 and the second planetary gears 30 connected in a state of being aligned in the direction of the central axis Ac. The carrier 50 includes two planet support shafts 51, a fixing bolt 55, a connecting bolt 56, a first carrier member 60, and a second carrier member 70.

  The first carrier member 60 is disposed on the input side (left side in FIG. 1) of the power transmission device 1 and supports one end of the two planet support shafts 51. The second carrier member 70 is disposed on the output side (the right side in FIG. 1) of the power transmission device 1 and supports the other ends of the two planet support shafts 51. The first carrier member 60 is integrally fixed by screwing the first carrier body 61 and the first support plate 62 with fixing bolts 55. Similarly, the second carrier member 70 is integrally fixed by screwing the second carrier main body 71 and the second support plate 72 with fixing bolts 55.

  Here, in the planetary mechanism assembled to the power transmission device 1, the outer edges of the flanges 23 and 33 constituting the outermost parts of the first planetary gear 20 and the second planetary gear 30 are the first sun gear 11 and the second sun gear. It is located radially outward from the innermost part of the gear 12. Therefore, when the assembly composed of the first planetary gear 20, the second planetary gear 30, and the carrier 50 is arranged on the inner peripheral side of the housing 2, the flanges for the first sun gear 11 and the second sun gear 12 are arranged. It is necessary to prevent the interference of 23 and 33. Therefore, in the present embodiment, the carrier 50 employs a mechanism that allows movement of the temporarily assembled planetary support shaft 51 in the radial direction.

  Specifically, the first carrier main body 61 and the second carrier main body 71 are formed with long holes 61 a and 71 a that penetrate in the direction of the central axis Ac and extend in the radial direction of the carrier 50. Further, the first support plate 62 and the second support plate 72 are formed with U-shaped grooves 62 a and 72 a that open outward in the radial direction of the carrier 50. The long holes 61a and 71a allow the planetary support shaft 51 temporarily assembled in the long holes 61a and 71a to move in the radial direction (vertical direction in FIG. 1) in the planetary mechanism assembling process. Thereby, interference of each flange 23 and 33 with respect to the 1st sun gear 11 and the 2nd sun gear 12 is prevented.

  And the 1st planetary gear 20 (2nd planetary gear 30) in the state where the 1st toothed belt 41 (2nd toothed belt 42) was interposed between the 1st sun gear 11 (2nd sun gear 12). After the phase alignment is performed, the planetary support shaft 51 is moved outside the long holes 61a and 71a. In this state, the first support plate 62 is fixed to the first carrier body 61 and the second support plate 72 is fixed to the second carrier body 71. Thereby, one end of the planetary support shaft 51 is sandwiched and supported between the long hole 61 a of the first carrier body 61 and the U-shaped groove 62 a of the first support plate 62. Similarly, the other end of the planetary support shaft 51 is sandwiched and supported between the long hole 71 a of the second carrier body 71 and the U-shaped groove 72 a of the second support plate 72.

  Further, the second carrier body 71 has a connecting portion 71 c extending from the surface facing the first carrier body 61 in the direction of the central axis Ac. The first carrier member 60 and the second carrier member 70 are integrally connected to each other by being screw-fastened by a connecting bolt 56 in a state where the first carrier body 61 is in contact with the end surface of the connecting portion 71c of the second carrier body 71. The The first carrier member 60 and the second carrier member 70 are jigs (not shown) penetrating the first support plate 62 and the second support plate 72 at both ends of the two planet support shafts 51 supported by both ends. ) And are integrally connected via the planetary support shaft 51.

  The carrier 50 has a plurality of key grooves 61 b formed on the inner peripheral surface of the first carrier body 61 and a plurality of key grooves 71 b formed on the inner peripheral surface of the second carrier body 71 on the outer peripheral surface of the input shaft 3. The key groove 3a is disposed so as to face the key groove 3a. In this state, the carrier 50 is prevented from rotating with respect to the input shaft 3 by inserting the key members 81 and 82 into the respective key grooves 61b, 71b, and 3a.

(Operation of the power transmission device 1)
The power transmission device 1 having such a configuration includes a first sun gear 11, a second sun gear 12, a first planetary gear 20, a second planetary gear 30, a first toothed belt 41, a second toothed belt 42, And a planetary mechanism having the carrier 50 as a transmission element. The planetary mechanism of the power transmission device 1 employs a meshing type in which each transmission element is engaged by meshing.

  In the power transmission device 1, when rotational power is input from the input shaft 3, the first planetary gear 20 and the second planetary gear 30 supported by the carrier 50 revolve around the center axis Ac. At this time, the first sun gear 11 is fixed to the housing 2 and its rotation is restricted. Therefore, the first toothed belt 41 that is partially pressed against the first sun gear 11 by the two first planetary gears 20 is connected to the first sun gear 11 along with the revolution movement of the first planetary gear 20. Rotate along the path so that the meshing position moves in the circumferential direction.

  As the first toothed belt 41 rotates, the first planetary gear 20 that meshes with the first toothed belt 41 rotates. The second planetary gear 30 connected integrally with the first planetary gear 20 revolves with the rotation of the carrier 50, and rotates at the same rotation speed as the first planetary gear 20 rotates. As a result, the second toothed belt 42 wound around the outer circumferences of the two second planetary gears 30 rotates along the path.

  The second toothed belt 42 is partially pressed against the second sun gear 12 by the two second planetary gears 30. Therefore, the meshing position of the second toothed belt 42 with the second sun gear 12 moves in the circumferential direction as the second planetary gear 30 revolves. With the rotation of the second toothed belt 42 and the movement of the meshing position, the second sun gear 12 that meshes with the second toothed belt 42 rotates around the center axis Ac.

  Here, in the present embodiment, the number of external teeth 41a of the first toothed belt 41 is set equal to the number of internal teeth 41b. Similarly, the number of outer teeth 42a of the second toothed belt 42 is set equal to the number of inner teeth 42b. Therefore, the gear ratio of the power transmission device 1 is defined according to the number of teeth of each of the first sun gear 11, the second sun gear 12, the first planetary gear 20, and the second planetary gear 30. The rotational speed of the second sun gear 12 is the product of the transmission ratio of the power transmission device 1 and the rotational speed of the input shaft 3. The power transmission device 1 transmits the shifted rotational power from the second sun gear 12 to the output shaft 4 via the cylindrical member 5 and outputs it.

<Modification of Embodiment>
(Planet mechanism of power transmission device 1)
In the embodiment, the first toothed belt 41 and the second toothed belt 42 constituting the planetary mechanism of the power transmission device 1 have the same number of outer teeth 41a, 42a and inner teeth 41b, 42b. . On the other hand, one or both of the first toothed belt 41 and the second toothed belt 42 may be configured such that the number of outer teeth 41a, 42a and the number of inner teeth 41b, 42b are set to different values. .

  Thereby, it becomes possible to increase / decrease the gear ratio by meshing with the first toothed belt 41 and the second toothed belt 42 interposed. For example, when the number of outer teeth 41 a and the number of inner teeth 41 b of the first toothed belt 41 are set to different values, the first planetary gear 20 is sandwiched between the first sun gear 11 and the first sun gear 11. When meshed with the one-tooth belt 41, the rotational speed of the rotation of the first planetary gear 20 changes by an amount corresponding to the difference in the number of teeth of the external teeth 41a and the internal teeth 41b, and the power transmission device 1 The gear ratio is increased or decreased.

  More specifically, in the configuration exemplified in the embodiment (the configuration in which the rotational power input from the carrier 50 is shifted and output from the second sun gear 12), the number of external teeth 41a of the first toothed belt 41 is the same. On the other hand, when the number of the inner teeth 41b is set to be small, the reduction gear ratio is increased as compared with the configuration having no difference in the number of teeth. On the other hand, when the number of the inner teeth 42b is set to be smaller than the number of the outer teeth 42a of the second toothed belt 42, the speed reduction ratio becomes smaller compared to a configuration in which there is no difference in the number of teeth.

  According to such a configuration, the gear ratio can be set by the difference in the number of teeth in the first toothed belt 41 and the second toothed belt 42. Therefore, in the power transmission device 1, the first sun gear 11 and the second sun gear 12 can be internal gears set to the same gear specifications. Thereby, it becomes possible to make the 1st sun gear 11 and the 2nd sun gear 12 into a common component, or to produce | generate by a common process, and can reduce manufacturing cost.

  Moreover, in embodiment, the power transmission device 1 is the 1st toothed belt 41 and the 2nd toothed belt 42 with respect to the 1st sun gear 11 and the 2nd sun gear 12 arrange | positioned in parallel with the center axis line Ac direction. The first planetary gear 20 and the second planetary gear 30 are indirectly engaged by meshing with each other. On the other hand, any one of the planetary gears may be configured to directly engage with the sun gear without using a transmission member.

  In the embodiment, the power transmission device 1 employs a meshing planetary mechanism in which transmission elements are engaged by meshing. On the other hand, the power transmission device 1 may employ a friction planetary mechanism in which transmission elements engage with each other by friction. Further, the power transmission device 1 may employ a planetary mechanism in which a meshing type and a friction type are appropriately combined.

  For example, the first solar wheel, the first planetary wheel, and the first transmission member are engaged by friction, and the second solar wheel, the second planetary wheel, and the second transmission member that transmit relatively large rotational power. It is good also as engagement by meshing similarly to embodiment. In addition, it is good also as a structure which carries out engagement by engagement between a solar wheel and a transmission member, and engages between a planetary wheel and a transmission member by friction.

  In the embodiment, the first transmission member and the second transmission member are the first toothed belt 41 and the second toothed belt 42 which are endless belt members. On the other hand, when the movable range of the power transmission device 1 is limited, for example, the first transmission member is an end portion that spans at least a part of the outer periphery of the two first planetary gears 20. It is good also as a structure which has. The same applies to the second transmission member.

  In the embodiment, the power transmission device 1 includes two first planetary gears 20 and two second planetary gears 30. On the other hand, the power transmission device 1 may be configured to include three or more first planetary gears 20 and two second planetary gears 30. For example, when the power transmission device 1 includes three or more first planetary gears 20, the first toothed belt 41 may be stretched around the outer periphery of the three first planetary gears 20. The two first planetary gears 20 may be spanned as a set, respectively.

<Effects of Configuration of Embodiment and Modification>
In the embodiment, the power transmission device 1 includes a first sun wheel (first sun gear 11) and a second sun wheel (second sun gear 12), which are inscribed vehicles arranged coaxially on the central axis Ac. A plurality of first planetary gears (first planetary gears 20) arranged on the inner peripheral side of the first sun wheel (first sun gear 11) and the outer circumferences of the plurality of first planetary gears (first planetary gears 20). A first transmission member (first toothed belt 41) that is wound around and inscribed in engagement with the first sun wheel (first sun gear 11), and the inner periphery of the second sun wheel (second sun gear 12) And a plurality of second planetary gears (second planetary gears 30) provided integrally with a plurality of first planetary gears (first planetary gears 20) and a plurality of second planetary vehicles (second planetary gears 30). The second transmission member (second toothed belt 4) is wound around the outer periphery of the gear 30) and inscribed in engagement with the second sun wheel (second sun gear 12). Comprising a) a carrier 50 supporting a plurality of first planet wheel (the first planetary gear 20) and a plurality of second planetary wheel (second planetary gear 30) rotatably, a.

  According to such a configuration, the first toothed belt 41 is interposed between the first sun gear 11 and the first planetary gear 20, and the second sun gear 12 and the second planetary gear 30 are Rotational power is transmitted between the two members via the double-toothed belt 42. The first toothed belt 41 and the second toothed belt 42 are stretched over the first planetary gear 20 and the second planetary gear 30 that are integrally provided, and the other rotates in response to one rotation.

  That is, the first toothed belt 41 and the second toothed belt 42 correspond to flex splines that mesh with each of a set of circular splines of the wave gear mechanism. The first toothed belt 41 is pressed against the first sun gear 11 by the first planetary gear 20 and bends and engages with the first sun gear 11 while being bent. The second toothed belt 42 is pressed against the second sun gear 12 by the second planetary gear 30 and is inscribed and engaged with the second sun gear 12 while being bent.

  Thereby, in the wave gear mechanism, the flex spline is configured to mesh with different internal gears (a set of circular splines) in the tooth width direction, whereas in the configuration of the present embodiment, the first tooth made of a separate member is used. The belt 41 and the second toothed belt 42 are engaged with different inscribed vehicles (the first sun gear 11 and the second sun gear 12). Therefore, compared with the strength required for the flex spline, the required strength of each member is reduced, so that the size of the apparatus can be reduced while suppressing an increase in manufacturing cost.

  Further, by applying the configuration as described above, it is possible to apply a meshing type and friction type planetary mechanism to the power transmission device 1. Since the first toothed belt 41 and the second toothed belt 42 are separate members, in the case of the meshing planetary mechanism, there is no structural restriction like the wave gear mechanism, so the gear specifications Setting flexibility can be improved. In the case of a friction type planetary mechanism, the degree of freedom in setting the outer diameter and inner diameter of the friction wheel can be improved.

In the embodiment, the first sun wheel (first sun gear 11) and the second sun wheel (second sun gear 12) are internal gears. The first transmission member is a toothed belt (first toothed belt 41) having external teeth 41a meshing with the first sun wheel (first sun gear 11). The second transmission member is a toothed belt (second toothed belt 42) having external teeth 42a meshing with the second sun wheel (second sun gear 12).
According to such a configuration, the power transmission device 1 employs a meshing type between the first sun gear 11 and the first toothed belt 41 and between the second sun gear 12 and the second toothed belt 42. To do. Therefore, it is possible to transmit strong rotational power between these members as compared with the configuration employing the friction type.

In the embodiment, the first planetary gear (first planetary gear 20) and the second planetary gear (second planetary gear 30) are external gears. The first transmission member is a toothed belt (first toothed belt 41) having internal teeth 41b meshing with the first planetary gear (first planetary gear 20). The second transmission member is a toothed belt (second toothed belt 42) having internal teeth 42b meshing with the second planetary wheel (second planetary gear 30).
According to such a configuration, the power transmission device 1 employs a meshing type between the first planetary gear 20 and the first toothed belt 41 and between the second planetary gear 30 and the second toothed belt 42. To do. Therefore, it is possible to transmit strong rotational power between these members as compared with the configuration employing the friction type.

Moreover, in a deformation | transformation aspect, the number of the external teeth 41a of a 1st transmission member (1st toothed belt 41) is set to a different value from the number of the internal teeth 41b of the said 1st transmission member (1st toothed belt 41). Is done. The number of external teeth 42a of the second transmission member (second toothed belt 42) is set to a value different from the number of internal teeth 42b of the second transmission member (second toothed belt 42).
According to such a configuration, when rotational power is transmitted between the first sun gear 11 and the first planetary gear 20, both members are engaged by the engagement of the first toothed belt 41 interposed between the two members. A rotational difference between the two can be produced. Similarly, between the second sun gear 12 and the second planetary gear 30, a rotation difference between the two members can be generated by meshing the second toothed belt 42. That is, the rotational power can be changed by applying a transmission member (the first toothed belt 41 and the second toothed belt 42) having a difference in the number of teeth between the outer teeth 41a and 42a and the inner teeth 41b and 42b. . Therefore, the gear ratio can be further increased.

In the modification, the first sun wheel (first sun gear 11) and the second sun wheel (second sun gear 12) are set to the same gear specifications.
According to such a configuration, the gear ratio is set by the difference in the number of teeth of the external teeth 41a, 42a and the internal teeth 41b, 42b in the first toothed belt 41 and the second toothed belt 42, and the first sun gear 11 and the first The two sun gears 12 can be made to be internal gears having the same gear specifications. Here, the manufacturing cost of the internal gear is generally relatively higher than the manufacturing cost of the external gear. In particular, when two internal gears set to different gear specifications are formed, there is a concern that the manufacturing cost may be significantly increased depending on the processing method.

  On the other hand, for example, in a planetary mechanism adopting a stepped planetary gear having two planetary gears set to different gear specifications, the two planetary gears are connected in a coaxially arranged state, Two sun gears cannot be internal gears having the same gear specifications. On the other hand, according to the above configuration, since the transmission member is interposed between the sun gear and the planetary gear, there is a degree of freedom in setting the distance between the sun gear and the planetary gear. The two sun gears 12 can be made to be internal gears having the same gear specifications. Therefore, since the 1st sun gear 11 and the 2nd sun gear 12 can be made into a common part, or can be produced | generated by a common process, manufacturing cost can be reduced.

  Moreover, in a deformation | transformation aspect, the power transmission device 1 was arrange | positioned at the inner peripheral side of the 1st solar vehicle and the 1st solar vehicle which are the inscribed vehicles arrange | positioned coaxially on center axis line Ac, and a 1st solar vehicle. A plurality of first planetary wheels, a first transmission member that is wound around the outer periphery of the plurality of first planetary wheels and inscribed and engaged with the first solar wheel, and inscribed and engaged with the second solar wheel, A second planetary gear provided integrally with the plurality of first planetary vehicles; and a plurality of first planetary vehicles and a carrier 50 that rotatably supports the second planetary vehicles.

  According to such a configuration, the first transmission member is interposed between the first solar wheel and the first planetary wheel, and rotational power is transmitted between the two members. Further, the first transmission member is stretched over the first planetary gear provided integrally with the second planetary vehicle, and rotates in conjunction with the rotation of the second planetary vehicle. That is, the first transmission member corresponds to a flex spline that meshes with each of a set of circular splines of the wave gear mechanism. The first transmission member is inscribed and engaged with the first solar wheel while being bent by being pressed against the first solar wheel by the first planetary wheel.

  Thereby, in the wave gear mechanism, the flex spline is configured to mesh with different internal gears (a set of circular splines) in the tooth width direction, whereas in this configuration, the first transmission member and the second planetary gear are Engage with different inscribed vehicles (first and second solar wheels). Therefore, compared with the strength required for the flex spline, the required strength of each member is reduced, so that the size of the apparatus can be reduced while suppressing an increase in manufacturing cost.

  Further, by applying the above-described configuration, it is possible to apply a meshing type and friction type planetary mechanism to the power transmission device. And, since the first transmission member and the second planetary gear, which are separate members, are respectively engaged with the first solar wheel and the second solar wheel that are the two inscribed vehicles, in the case of the meshing planetary mechanism, Since there are no structural restrictions like the wave gear mechanism, the degree of freedom in setting the gear specifications can be improved. In the case of a friction type planetary mechanism, the degree of freedom in setting the outer diameter and inner diameter of the friction wheel can be improved.

In the embodiment and the modification, the first sun wheel (first sun gear 11) is an internal gear. The first transmission member (first toothed belt 41) is a toothed belt having external teeth that mesh with the first sun wheel (first sun gear 11).
According to such a configuration, the power transmission device 1 employs a meshing type between the first sun gear 11 and the first toothed belt 41. Therefore, it is possible to transmit strong rotational power between these members as compared with the configuration employing the friction type.

In the embodiment and the modification, the first planetary wheel (first planetary gear 20) is an external gear. The first transmission member (first toothed belt 41) is a toothed belt having internal teeth that mesh with the first planetary gear (first planetary gear 20).
According to such a configuration, the power transmission device 1 employs a meshing type between the first planetary gear 20 and the first toothed belt 41. Therefore, it is possible to transmit strong rotational power between these members as compared with the configuration employing the friction type.

Moreover, in a deformation | transformation aspect, the number of the external teeth 41a of a 1st transmission member (1st toothed belt 41) is set to a different value from the number of the internal teeth 41b of the said 1st transmission member (1st toothed belt 41). Is done.
According to such a configuration, when rotational power is transmitted between the first sun gear 11 and the first planetary gear 20, both members are engaged by the engagement of the first toothed belt 41 interposed between the two members. A rotational difference between the two can be produced. That is, the rotational power can be changed by applying a transmission member (first toothed belt 41) having a difference in the number of teeth between the outer teeth 41a and the inner teeth 41b. Therefore, the gear ratio can be further increased.

  1: power transmission device 11: first sun gear (first sun wheel) 12: second sun gear (second sun wheel) 20: first planetary gear (first planet wheel) 30: second planet Gear (second planetary gear), 41: first toothed belt (first transmission member), 41a: external teeth, 41b: internal teeth, 42: second toothed belt (second transmission member), 42a: external teeth 42b: internal teeth, 50: carrier, Ac: central axis, Ap: rotation axis (of planetary gear)

Claims (9)

A first solar wheel and a second solar wheel, which are inscribed vehicles arranged coaxially on the central axis,
A plurality of first planetary vehicles arranged on the inner peripheral side of the first solar wheel;
A first transmission member spanned around the outer periphery of the plurality of first planetary wheels and inscribed in engagement with the first solar wheel;
A plurality of second planetary vehicles disposed on the inner peripheral side of the second solar wheel and provided integrally with the plurality of first planetary vehicles;
A second transmission member that is wound around the outer periphery of the plurality of second planetary wheels and inscribed in engagement with the second solar wheel;
A carrier that rotatably supports the plurality of first planetary vehicles and the plurality of second planetary vehicles;
A power transmission device comprising: The first sun wheel and the second sun wheel are internal gears,
The first transmission member is a toothed belt having external teeth meshing with the first solar wheel,
The power transmission device according to claim 1, wherein the second transmission member is a toothed belt having external teeth meshing with the second solar wheel. The first planetary vehicle and the second planetary vehicle are external gears,
The first transmission member is a toothed belt having internal teeth meshing with the first planetary wheel,
3. The power transmission device according to claim 2, wherein the second transmission member is a toothed belt having internal teeth meshing with the second planetary wheel. The number of external teeth of the first transmission member is set to a value different from the number of internal teeth of the first transmission member,
The power transmission device according to claim 3, wherein the number of external teeth of the second transmission member is set to a value different from the number of internal teeth of the second transmission member.   The power transmission device according to claim 4, wherein the first solar wheel and the second solar wheel are set to the same gear specifications. A first solar wheel and a second solar wheel, which are inscribed vehicles arranged coaxially on the central axis,
A plurality of first planetary vehicles arranged on the inner peripheral side of the first solar wheel;
A first transmission member spanned around the outer periphery of the plurality of first planetary wheels and inscribed in engagement with the first solar wheel;
A second planetary wheel that is inscribed and engaged with the second solar wheel and is provided integrally with the plurality of first planetary wheels;
A plurality of the first planetary wheel, a carrier that rotatably supports the second planetary car,
A power transmission device comprising: The first sun wheel is an internal gear;
The power transmission device according to claim 1 or 6, wherein the first transmission member is a toothed belt having external teeth meshing with the first solar wheel. The first planetary wheel is an external gear,
The power transmission device according to claim 7, wherein the first transmission member is a toothed belt having internal teeth that mesh with the first planetary gear.   The power transmission device according to claim 8, wherein the number of external teeth of the first transmission member is set to a value different from the number of internal teeth of the first transmission member.

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